HD404849 Datasheet, PDF (97/125 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404849 Series
LCD Controller/Driver
The MCU has an LCD controller and driver which drive 4 common signal pins and 32 segment pins. The
controller consists of a RAM area in which display data is stored, a display control register (LCR: $01B),
and a duty-cycle/clock-control register (LMR: $01C) (figure 84).
Four duty cycles and the LCD clock are programmable, and a built-in dual-port RAM ensures that display
data can be automatically transmitted to the segment signal pins without program intervention. If a 32-kHz
oscillation clock is selected as the LCD clock source, the LCD can even be used in watch mode, in which
the system clock stops.
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